1. Field of the Invention:
The present invention relates to a tiltable roller assembly for attachment to movable closure means such as a door or a window sash.
2. Prior Art:
Tiltable roller assemblies have a tiltable roller which allows a window sash equipped with the assembly to move sideways in a direction parallel to the axis of the roller, thereby facilitating the locking of the window sash. One known such assembly is disclosed in Japanese Laid-Open Utility Model Publication No. 52-34548, published Mar. 11, 1977, and comprises an outer frame attachable to the lower rail of a window sash and an inner frame pivotally mounted in the outer frame and supporting a roller rotatably thereon. The inner frame is vertically adjustable by a screw extending threadedly through the outer frame into abutting engagement with the inner frame. Spring means act between the outer frame and the inner frame to urge the inner frame against one sidewall of the outer frame. Since the adjustment screw abuts directly against the inner frame, the screw and inner frame become gradually worn away as the inner frame is repeatedly tilted back and forth, requiring frequent vertical readjustments of the roller. When the adjustment screw is tightened excessively, the tilting movement of the inner frame becomes sluggish or even impossible.
Another disadvantage with the prior tiltable roller assembly is that it must be available in two symmetrical constructions, one being the mirror image of the other, so as to make the adjustment screws easily accessible when they are located at both ends of the lower rail of a window sash.